src/common/consumer-stream.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <assert.h>
  22 #include <inttypes.h>
  23 #include <sys/mman.h>
  24 #include <unistd.h>
  25
  26 #include <common/common.h>
  27 #include <common/index/index.h>
  28 #include <common/relayd/relayd.h>
  29 #include <common/ust-consumer/ust-consumer.h>
  30
  31 #include "consumer-stream.h"
  32
  33 /*
  34  * RCU call to free stream. MUST only be used with call_rcu().
  35  */
  36 static void free_stream_rcu(struct rcu_head *head)
  37 {
  38         struct lttng_ht_node_u64 *node =
  39                 caa_container_of(head, struct lttng_ht_node_u64, head);
  40         struct lttng_consumer_stream *stream =
  41                 caa_container_of(node, struct lttng_consumer_stream, node);
  42
  43         pthread_mutex_destroy(&stream->lock);
  44         free(stream);
  45 }
  46
  47 /*
  48  * Close stream on the relayd side. This call can destroy a relayd if the
  49  * conditions are met.
  50  *
  51  * A RCU read side lock MUST be acquired if the relayd object was looked up in
  52  * a hash table before calling this.
  53  */
  54 void consumer_stream_relayd_close(struct lttng_consumer_stream *stream,
  55                 struct consumer_relayd_sock_pair *relayd)
  56 {
  57         int ret;
  58
  59         assert(stream);
  60         assert(relayd);
  61
  62         if (stream->sent_to_relayd) {
  63                 uatomic_dec(&relayd->refcount);
  64                 assert(uatomic_read(&relayd->refcount) >= 0);
  65         }
  66
  67         /* Closing streams requires to lock the control socket. */
  68         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
  69         ret = relayd_send_close_stream(&relayd->control_sock,
  70                         stream->relayd_stream_id,
  71                         stream->next_net_seq_num - 1);
  72         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
  73         if (ret < 0) {
  74                 DBG("Unable to close stream on the relayd. Continuing");
  75                 /*
  76                  * Continue here. There is nothing we can do for the relayd.
  77                  * Chances are that the relayd has closed the socket so we just
  78                  * continue cleaning up.
  79                  */
  80         }
  81
  82         /* Both conditions are met, we destroy the relayd. */
  83         if (uatomic_read(&relayd->refcount) == 0 &&
  84                         uatomic_read(&relayd->destroy_flag)) {
  85                 consumer_destroy_relayd(relayd);
  86         }
  87         stream->net_seq_idx = (uint64_t) -1ULL;
  88         stream->sent_to_relayd = 0;
  89 }
  90
  91 /*
  92  * Close stream's file descriptors and, if needed, close stream also on the
  93  * relayd side.
  94  *
  95  * The consumer data lock MUST be acquired.
  96  * The stream lock MUST be acquired.
  97  */
  98 void consumer_stream_close(struct lttng_consumer_stream *stream)
  99 {
 100         int ret;
 101         struct consumer_relayd_sock_pair *relayd;
 102
 103         assert(stream);
 104
 105         switch (consumer_data.type) {
 106         case LTTNG_CONSUMER_KERNEL:
 107                 if (stream->mmap_base != NULL) {
 108                         ret = munmap(stream->mmap_base, stream->mmap_len);
 109                         if (ret != 0) {
 110                                 PERROR("munmap");
 111                         }
 112                 }
 113
 114                 if (stream->wait_fd >= 0) {
 115                         ret = close(stream->wait_fd);
 116                         if (ret) {
 117                                 PERROR("close");
 118                         }
 119                         stream->wait_fd = -1;
 120                 }
 121                 break;
 122         case LTTNG_CONSUMER32_UST:
 123         case LTTNG_CONSUMER64_UST:
 124                 break;
 125         default:
 126                 ERR("Unknown consumer_data type");
 127                 assert(0);
 128         }
 129
 130         /* Close output fd. Could be a socket or local file at this point. */
 131         if (stream->out_fd >= 0) {
 132                 ret = close(stream->out_fd);
 133                 if (ret) {
 134                         PERROR("close");
 135                 }
 136                 stream->out_fd = -1;
 137         }
 138
 139         if (stream->index_fd >= 0) {
 140                 ret = close(stream->index_fd);
 141                 if (ret) {
 142                         PERROR("close stream index_fd");
 143                 }
 144                 stream->index_fd = -1;
 145         }
 146
 147         /* Check and cleanup relayd if needed. */
 148         rcu_read_lock();
 149         relayd = consumer_find_relayd(stream->net_seq_idx);
 150         if (relayd != NULL) {
 151                 consumer_stream_relayd_close(stream, relayd);
 152         }
 153         rcu_read_unlock();
 154 }
 155
 156 /*
 157  * Delete the stream from all possible hash tables.
 158  *
 159  * The consumer data lock MUST be acquired.
 160  * The stream lock MUST be acquired.
 161  */
 162 void consumer_stream_delete(struct lttng_consumer_stream *stream,
 163                 struct lttng_ht *ht)
 164 {
 165         int ret;
 166         struct lttng_ht_iter iter;
 167
 168         assert(stream);
 169         /* Should NEVER be called not in monitor mode. */
 170         assert(stream->chan->monitor);
 171
 172         rcu_read_lock();
 173
 174         if (ht) {
 175                 iter.iter.node = &stream->node.node;
 176                 ret = lttng_ht_del(ht, &iter);
 177                 assert(!ret);
 178         }
 179
 180         /* Delete from stream per channel ID hash table. */
 181         iter.iter.node = &stream->node_channel_id.node;
 182         /*
 183          * The returned value is of no importance. Even if the node is NOT in the
 184          * hash table, we continue since we may have been called by a code path
 185          * that did not add the stream to a (all) hash table. Same goes for the
 186          * next call ht del call.
 187          */
 188         (void) lttng_ht_del(consumer_data.stream_per_chan_id_ht, &iter);
 189
 190         /* Delete from the global stream list. */
 191         iter.iter.node = &stream->node_session_id.node;
 192         /* See the previous ht del on why we ignore the returned value. */
 193         (void) lttng_ht_del(consumer_data.stream_list_ht, &iter);
 194
 195         rcu_read_unlock();
 196
 197         /* Decrement the stream count of the global consumer data. */
 198         assert(consumer_data.stream_count > 0);
 199         consumer_data.stream_count--;
 200 }
 201
 202 /*
 203  * Free the given stream within a RCU call.
 204  */
 205 void consumer_stream_free(struct lttng_consumer_stream *stream)
 206 {
 207         assert(stream);
 208
 209         call_rcu(&stream->node.head, free_stream_rcu);
 210 }
 211
 212 /*
 213  * Destroy the stream's buffers of the tracer.
 214  */
 215 void consumer_stream_destroy_buffers(struct lttng_consumer_stream *stream)
 216 {
 217         assert(stream);
 218
 219         switch (consumer_data.type) {
 220         case LTTNG_CONSUMER_KERNEL:
 221                 break;
 222         case LTTNG_CONSUMER32_UST:
 223         case LTTNG_CONSUMER64_UST:
 224                 lttng_ustconsumer_del_stream(stream);
 225                 break;
 226         default:
 227                 ERR("Unknown consumer_data type");
 228                 assert(0);
 229         }
 230 }
 231
 232 /*
 233  * Destroy and close a already created stream.
 234  */
 235 static void destroy_close_stream(struct lttng_consumer_stream *stream)
 236 {
 237         assert(stream);
 238
 239         DBG("Consumer stream destroy monitored key: %" PRIu64, stream->key);
 240
 241         /* Destroy tracer buffers of the stream. */
 242         consumer_stream_destroy_buffers(stream);
 243         /* Close down everything including the relayd if one. */
 244         consumer_stream_close(stream);
 245 }
 246
 247 /*
 248  * Decrement the stream's channel refcount and if down to 0, return the channel
 249  * pointer so it can be destroyed by the caller or NULL if not.
 250  */
 251 static struct lttng_consumer_channel *unref_channel(
 252                 struct lttng_consumer_stream *stream)
 253 {
 254         struct lttng_consumer_channel *free_chan = NULL;
 255
 256         assert(stream);
 257         assert(stream->chan);
 258
 259         /* Update refcount of channel and see if we need to destroy it. */
 260         if (!uatomic_sub_return(&stream->chan->refcount, 1)
 261                         && !uatomic_read(&stream->chan->nb_init_stream_left)) {
 262                 free_chan = stream->chan;
 263         }
 264
 265         return free_chan;
 266 }
 267
 268 /*
 269  * Destroy a stream completely. This will delete, close and free the stream.
 270  * Once return, the stream is NO longer usable. Its channel may get destroyed
 271  * if conditions are met for a monitored stream.
 272  *
 273  * This MUST be called WITHOUT the consumer data and stream lock acquired if
 274  * the stream is in _monitor_ mode else it does not matter.
 275  */
 276 void consumer_stream_destroy(struct lttng_consumer_stream *stream,
 277                 struct lttng_ht *ht)
 278 {
 279         assert(stream);
 280
 281         /* Stream is in monitor mode. */
 282         if (stream->monitor) {
 283                 struct lttng_consumer_channel *free_chan = NULL;
 284
 285                 /*
 286                  * This means that the stream was successfully removed from the streams
 287                  * list of the channel and sent to the right thread managing this
 288                  * stream thus being globally visible.
 289                  */
 290                 if (stream->globally_visible) {
 291                         pthread_mutex_lock(&consumer_data.lock);
 292                         pthread_mutex_lock(&stream->chan->lock);
 293                         pthread_mutex_lock(&stream->lock);
 294                         /* Remove every reference of the stream in the consumer. */
 295                         consumer_stream_delete(stream, ht);
 296
 297                         destroy_close_stream(stream);
 298
 299                         /* Update channel's refcount of the stream. */
 300                         free_chan = unref_channel(stream);
 301
 302                         /* Indicates that the consumer data state MUST be updated after this. */
 303                         consumer_data.need_update = 1;
 304
 305                         pthread_mutex_unlock(&stream->lock);
 306                         pthread_mutex_unlock(&stream->chan->lock);
 307                         pthread_mutex_unlock(&consumer_data.lock);
 308                 } else {
 309                         /*
 310                          * If the stream is not visible globally, this needs to be done
 311                          * outside of the consumer data lock section.
 312                          */
 313                         free_chan = unref_channel(stream);
 314                 }
 315
 316                 if (free_chan) {
 317                         consumer_del_channel(free_chan);
 318                 }
 319         } else {
 320                 destroy_close_stream(stream);
 321         }
 322
 323         /* Free stream within a RCU call. */
 324         consumer_stream_free(stream);
 325 }
 326
 327 /*
 328  * Write index of a specific stream either on the relayd or local disk.
 329  *
 330  * Return 0 on success or else a negative value.
 331  */
 332 int consumer_stream_write_index(struct lttng_consumer_stream *stream,
 333                 struct lttng_packet_index *index)
 334 {
 335         int ret;
 336         struct consumer_relayd_sock_pair *relayd;
 337
 338         assert(stream);
 339         assert(index);
 340
 341         rcu_read_lock();
 342         relayd = consumer_find_relayd(stream->net_seq_idx);
 343         if (relayd) {
 344                 ret = relayd_send_index(&relayd->control_sock, index,
 345                                 stream->relayd_stream_id, stream->next_net_seq_num - 1);
 346         } else {
 347                 ret = index_write(stream->index_fd, index,
 348                                 sizeof(struct lttng_packet_index));
 349         }
 350         if (ret < 0) {
 351                 goto error;
 352         }
 353
 354 error:
 355         rcu_read_unlock();
 356         return ret;
 357 }